Structure of the Oesophagus and Morphometric, Histochemical–Immunohistochemical Profiles of the Oesophageal Gland During the Post‐hatching Period of Japanese Quails (Coturnix coturnix japonica)

Abstract

In the oesophagus, mucins, which originate from oesophageal submucosal glands, play an important role in the mucosal protection as a pre-epithelial barrier. In this study, the structure of cervical and thoracic parts of oesophagus of Japanese quail during the post-hatching period was compared, and the contents of carbohydrate and gastric mucin MUC5AC of the oesophageal glands in these parts were analysed at the light microscope levels by applying conventional histochemical and immunohistochemical methods. The oesophageal glands were present at hatching, located in the laminae propria. The numbers of glands were different in the cervical and thoracic parts, but the differences were found to be insignificant. The thoracic part has the oesophageal tonsils which are associated with the glands. Oesophageal tonsil was formed from day 5 after hatching. In quail of all ages, the secretory epithelium of glands contained neutral sialomucins and weakly sulphomucins. The cells in the neck region of secretory units contained sialomucins, while the cells of excretory ducts had strongly sulphomucins. Sialomucin containing cells in the secretory units increased with the advance of age and glandular development. But, in the secretory units, the sulphomucin content of glands was more in the thoracic part. The secretory epithelium of tonsil-associated glands contained mostly sulphomucins and a little sialomucin. From the hatching, MUC5AC mucin was detected in the cells of excretory ducts. Although the lymphoepithelium of the tonsil units exhibited negative reactions to all histochemical methods, it showed positive reaction to MUC5AC mucin antibody. In conclusion, the cervical and thoracic parts may be functionally different and the thoracic part of oesophagus was transformed into an immunological organ following day 5 after hatching.

Morphological features of the gastrointestinal tract of Garganey (Anas querquedula, Linnaeus 1758)—Oesophagus to coprodeum

“…Our findings revealed that the folds of the oesophagus were lined by non‐keratinized stratified squamous epithelium, which were in accordance with that obtained by Ma () and Sağsöz and Lıman (), while Rajabi and Nabipour () reported that the keratinization of the epithelium with different extent in various species of wild birds. Moreover, Hamdi, El‐Ghareeb, Zaher, and AbuAmod () in the black‐winged kite and Banks () in the pigeon recorded this keratinization.…”

Histological Study of the Oesophagus and Stomach in Grey-Backed Shrike (Lanius tephronotus)

“…The submucous layer was absent. This was coincided with the report of Sagsöz & Liman (2009). But Rajabi & Nabipour identified the submucous layer was located between the lamina muscularis mucosae and the muscular layer in the oesophagus of kestrel.…”

Mucin profiles of the abomasum in bulls and rams: A comparative study

“…Mucins protect the epithelium against chemical, enzymatic, and mechanical damage as well as from pathogenic microorganisms (Corfield et al, ; Sağsöz & Liman, ). In particular, sulfomucin shave an important role in protection against bacterial attack, as sulfation confers resistance to the enzymatic degradation of the mucus barrier by bacterial glycosidases or host proteases, such as pepsin (Brockhausen, ; Robertson & Wright, ; Sağsöz & Liman, ). Therefore, it can be said that sulfated mucins found in the abomasum provide primary protection against the colonization of the epithelial surface by microorganisms.…”

“…Acidic mucins are further classified as sulfated mucins (sulfomucins) and carboxylated mucins (sialomucins). While sulfated acidic mucins contain sulfated glucuronic acid, carboxylated acidic mucins contain sialic acid molecules (Erdoğan, Sağsöz, & Akbalık, ; Sağsöz & Liman, ; Sağsöz, Erdoğan, & Akbalik, ; Schumacher, Duku, Katoh, Jörns, & Krause, ). From a molecular perspective, all mucins contain a centrally located domain comprising numerous oligosaccharide chains.…”

“…For this purpose, conventional mucin histochemistry and immunohistochemistry were used. Given the high success of the histochemical method in the characterization of mucin carbohydrates (Schumacher et al, ; Sağsöz & Liman, ), first, the differences in the oligosaccharide side chains of the mucin glycoproteins in the luminal and glandular epithelium of the abomasum were examined. Second, the cellular immunolocalization and expression of MUC1, MUC2, MUC5AC, and MUC6 proteins in the luminal and glandular epithelium of the abomasum were evaluated and compared with each other.…”